Removal, processing and disposal of waste from 1 to 5 hazard class

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Water from a well or well is not always drinkable. To find out whether it is possible to cook with such water, a chemical analysis of the water is required. A complete chemical analysis of water may also be required to study the quality of tap or spring water, as well as for scientific purposes and as part of environmental monitoring.

During the analysis, the presented samples are examined for the presence of various contaminants: dissolved substances, insoluble compounds, bacteria and protozoa. In addition, it is possible to investigate the radioactivity of water. According to the results, laboratory assistants make a verdict - is it possible to use water for food, how suitable it is for domestic purposes, what pollutants it contains.

Sample collection

When sending samples for physical and chemical analysis of water, it must be remembered that there are rules for sampling:

• It is necessary to prepare a clean container - a bottle will do, in which before that there was non-carbonated clean drinking water.
• Before filling, it is recommended to rinse the container - you can use the same liquid that is intended for collection.

Rules are developed for each source. So, for collecting from a water tap, the algorithm is as follows:

• Open the tap for at least 10 minutes at medium pressure.
• Fill the bottle, being careful not to allow air bubbles to form.

For a well, the rules are similar:

• Open the tap for at least 10 minutes, maintain a medium pressure.
• If the well was abandoned or rarely used, then it is necessary to pump out the upper layer with a pump - at least 2 hours.

Rules for accurate analysis:

• A sample from the well is taken from a depth of 4 meters. The bucket must be clean.
• Sometimes bottom water may be required for a complete analysis of the well - it is collected in such a way as to exclude the ingress of silt and sand.
• When sampling into a bottle, it must be filled slowly.
• Immediately after sampling, the container must be tightly closed.
• It is best to give samples immediately. If this is not possible, the correct sample can be stored in the refrigerator for up to 2 days.

The sample is given along with an accompanying sheet. It indicates:

• Legal and actual address of the source.
• Source type.
• Exact date and time of sampling.
• Does water need urgent diagnostics?

The better the sample is collected, the more accurate the results of the study will be.

Indications for analysis

How do you know if research is needed? If you ask a specialist, the hygienist will say that it is best to carry out such an analysis regularly - even if it seems that there are no changes.

But there are situations in which water quality testing is not only recommended, but highly desirable:

1. If there is a noticeable change in color, smell or taste. In this case, it is worth sending the sample for examination as soon as possible. Until then, refrain from drinking. This is especially true for urban residents - water from underground sources often changes color depending on the amount of precipitation.
2. If construction was carried out near the well or well. Construction work at industrial facilities is especially dangerous. Microparticles of various toxic substances enter the water. If the reservoir is not flowing, they will linger for a long time.
3. When buying a plot next to a busy highway, it is worth checking the quality of drinking water from a well.
4. After emergencies at production facilities in the area of ​​the well. The analysis is required to make sure that toxic waste products do not get into the soil, and therefore into the water.
5. When choosing a filter for home use - to know what exactly needs to be filtered. Many companies offering turnkey filter installation services immediately offer an analysis. It is worth examining the water even after installing the filter - after a few months - to make sure that the equipment is working properly.

There are situations in which verification is provided for by federal law:

• Regularly - in medical, children's and health institutions.
• In the production of bottled drinking water.
• When opening new branches of the pipeline.
• At industrial enterprises - a mandatory examination of wastewater.

Similar requirements are contained in the Water Code of the Russian Federation, as well as in the draft Federal Law “On Water Supply” and the current Federal Law “On the Sanitary and Epidemiological Welfare of the Population”.

Regulations

Main types normative documents that establish quality requirements in Russia:

1. SanPiN - sanitary-toxicological and organoleptic indicators.
2. hygiene criteria.
3. epidemiological standards.
4. Medical criteria for assessing quality.
5. State standards for production.
6. Specifications.
7. Handbooks MPC.

Such a large number of standards is easily explained - after all, the harm from the use of water of inadequate quality for food purposes can be very serious.

tap water

When assessing quality using chemical-physical methods, the following indicators are evaluated:

• pH (the norm is in the range from 6 to 9).
• mineralization (the norm is not more than 1000 mg per liter).
• The content of individual chemical elements - a maximum threshold is set for each.
• Phenolic index.

In addition, a microbiological safety assessment is carried out, organoleptic properties and the content of certain classes of organic compounds are evaluated.

Bottled products

Bottled water is divided into two main categories - the highest and the first. The product of both categories must comply with the quality and safety standards prescribed in SanPiN. The difference is that the product of the highest category can only be obtained from certified natural sources, protected from pollution of any nature.

Quantitative chemical analysis evaluates the content of:

• Soleil.
• Gaza.
• organic impurities.

Also evaluate:

• General chemical composition.
• microbiological parameters.
• radiation indicators.
• The presence of toxic metals.

The examination is strictly regulated - there are guidelines for employees of quality assessment laboratories.

natural sources

Natural sources are:

• Wells and wells.
• Rivers and streams.
• Lakes and reservoirs.
• Springs.

The study of open sources is difficult, since their chemical composition is constantly changing - along with changes in weather, seasons and precipitation levels. There are individual guidelines for each open source. The most stringent regulations apply to springs, wells and wells - the water from them is often used for drinking without additional treatment.

Quality research

Water chemical analysis methods:

• Qualitative.
• Quantitative chemical analysis of water.

Qualitative allows you to establish the presence in the solution of any substances. And quantitative - their content.

To determine the quality, it is worth contacting a local expert organization or a SES branch. As a rule, specialists do not just conduct an analysis, but also issue recommendations for quality improvement.

Annex A (mandatory). Preparation of a cation exchanger (transfer to Preparation of a cation exchanger (transfer to H + - form) and activated carbon) and activated carbon

Quantitative chemical analysis of waters. Method for measuring the mass concentrations of sulfates in samples of natural and treated wastewater by titration with a barium salt in the presence of orthonyl K
PND F 14.1:2.107-97
(approved by the State Committee for Ecology of the Russian Federation on March 21, 1997)

1. Introduction

This document establishes a methodology for the quantitative chemical analysis of samples of natural and treated wastewater to determine in them mass concentration sulfates in the range from 50 to 300 by the titrimetric method without diluting and concentrating the sample.

If the mass concentration of sulfates in the analyzed sample exceeds the upper limit, it is allowed to dilute the sample with distilled water so that the concentration of sulfates corresponds to the regulated range.

If the mass concentration of sulfates in the analyzed sample is less than 50, another method of determination should be used.

The determination is hindered by colored and suspended solids, as well as cations that can react with orthonyl K.

Elimination of interfering influences is carried out in accordance with paragraph 10.

2. The principle of the method

The titrimetric method for determining the mass concentration of sulfates is based on the ability of sulfates to form a poorly soluble precipitate with barium ions. At the equivalence point, an excess of barium ions reacts with the indicator ortanyl K to form a complex compound. The color of the solution changes from blue-violet to greenish-blue.

3. Assigned characteristics of the measurement error and its components

This technique provides the results of the analysis with an error not exceeding the values ​​given in table 1.

The values ​​of the accuracy index of the methodology are used for:

Registration of the results of the analysis issued by the laboratory;

Evaluation of the activities of laboratories for the quality of testing;

Evaluation of the possibility of using the results of the analysis in the implementation of the methodology in a particular laboratory.

Table 1

Range of measurements, values ​​of indicators of accuracy, repeatability, reproducibility

4. Measuring instruments, auxiliary devices, reagents and materials

4.1. Measuring instruments

4.2. Auxiliary devices

Measuring instruments must be verified within the established time limits.

It is allowed to use other, including imported, measuring instruments and auxiliary devices with characteristics no worse than those given in p.p. 4.1 and 4.2.

4.3. Reagents and materials

All reagents used for analysis must be of analytical grade. or h.h.

It is allowed to use reagents manufactured according to other regulatory and technical documentation, including imported ones, with a qualification of at least analytical grade.

5. Safety requirements

5.1. When performing analyzes, it is necessary to comply with safety requirements when working with chemical reagents in accordance with GOST 12.1.007.

6. Qualification requirements for operators

Measurements can be performed by an analytical chemist who owns the technique of the titrimetric method of analysis.

7. Measurement conditions

When performing measurements in the laboratory, the following conditions must be met:

8. Sampling and storage

8.1. Sampling is carried out in accordance with the requirements of GOST R 51592-2000 "Water. General requirements for sampling".

8.2. The glassware intended for sampling and storage of samples is washed with a solution of hydrochloric acid and then with distilled water.

8.3. Water samples are taken in glass or polyethylene containers. The volume of the sample to be taken must be at least 200 .

8.4. Samples are stored at a temperature of 3-4°C. It is recommended to carry out the determination within 7 days after sampling.

If there are noticeable amounts of other mineral or organic sulfur compounds in the water, the determination must be carried out no later than 1 day after sampling.

8.5. When sampling, an accompanying document is drawn up in the approved form, which indicates:

Purpose of analysis, suspected contaminants;

Place, time of selection;

Sample number;

Position, name of the person taking the sample, date.

9. Preparing to take measurements

9.1. Preparation of solutions and reagents

9.1.1. Barium chloride solution, 0.02 equivalent.

Dissolve 1.22 g in 450 ml of distilled water in a 500 volumetric flask, make up to the mark with distilled water and mix. The solution is stored in a tightly closed bottle for no more than 6 months.

The exact concentration of the solution is determined by titrating the standard solution of potassium sulfate (section 9.2) at least once a month.

9.1.2. Standard solution of potassium sulfate with a concentration of 0.0200 equivalent.

0.4357 g, previously dried for 2 hours at 105-110°C, is transferred into a volumetric flask with a capacity of 250, brought to the mark with distilled water and mixed. Store in a tightly closed glass or plastic container for no more than 6 months.

9.1.3. Orthanilic K solution, 0.05%.

25 mg of orthonyl K are dissolved in 50 mg of distilled water. Store in a dark glass bottle for no more than 10 days at room temperature and no more than 1 month in the refrigerator.

9.1.4. Hydrochloric acid solution, 4 .

170 concentrated hydrochloric acid is mixed with 330 distilled water.

9.1.5. Hydrochloric acid solution, 1.

To 250 hydrochloric acid solution 4, add 750 distilled water and mix.

Solutions of hydrochloric acid are stable when stored in a tightly closed container for 1 year.

9.1.6. Sodium hydroxide solution, 1.

40 g NaOH is dissolved in 1 distilled water. Store in a tightly closed polyethylene container.

9.1.7. Sodium hydroxide solution, 0.4%.

2 g of sodium hydroxide is dissolved in 500 of distilled water. Store in a tightly closed polyethylene container.

Sodium hydroxide solutions are stable when stored in a tightly closed polyethylene container for 2 months.

9.2. Establishing the exact concentration of a barium chloride solution

In a conical flask with a capacity of 100, add 4 ml of a standard solution of potassium sulfate (clause 9.1.2), add 6 of water and adjust the pH of the solution to 4 with hydrochloric acid. Add 15% of ethyl alcohol or acetone, 0.3 of an ortanyl K solution and titrate with a barium chloride solution with constant stirring until the color changes from blue-violet to greenish-blue. The titration is carried out slowly, especially near the equivalence point, and continues until the violet color returns within 2-3 minutes.

The titration is repeated and in the absence of a discrepancy in the volumes of the titrant of more than 0.02, the arithmetic mean is taken as the result of the titration.

The exact concentration of a barium chloride solution is found by the formula:

where is the concentration of a solution of barium chloride, equivalent;

Concentration of potassium sulfate solution, equivalent;

Volume of potassium sulfate solution, ;

Volume of barium chloride solution used for titration of potassium sulfate solution, .

10. Elimination of interfering influences

The interfering effect of suspended and colloidal substances is eliminated by pre-filtering the sample.

If the water sample is visibly colored due to the presence of substances of natural or anthropogenic origin, it is difficult to fix the end point of the titration. In this case, before analysis, the sample should be passed at a speed of 4-6 through a chromatographic column filled with activated carbon (layer height 12-15 cm). The first 25-30 samples passing through the column are discarded.

If active chlorine is present in the sample, it is removed by heating the sample. To do this, the analyzed water is placed in a volumetric flask with a capacity of 100 to the mark, then the sample is transferred from the flask into a beaker with a capacity of 250 and boiled for 10-15 minutes. After cooling, the sample is returned to the volumetric flask, the glass is rinsed with 1-2 distilled water and the volume of the sample in the flask is adjusted to the mark.

The interfering effect of cations is eliminated by treating the sample with a cation exchanger.

11. Taking measurements

Immediately before performing the analysis, 5-10 g of the cation exchange resin is filtered on a funnel through a loose paper filter, placed in a conical flask with a capacity of 250 and rinsed with 20-25 of the analyzed water.

50-70% of analyzed water is added to the flask with cation exchange resin and the sample is kept for 10 minutes, periodically shaking the flask. Then the cation exchanger is allowed to settle and water is taken with a pipette 10 into a conical flask with a capacity of 100. Check the pH and, if necessary, adjust its value with sodium hydroxide solution 1 to approximately 4 on indicator paper. Add 15% ethyl alcohol or acetone, 0.3 solution of ortanyl K and titrate with a solution of barium chloride while constantly stirring the contents of the flask until the color changes from blue-violet to greenish-blue.

In the initial stage of the titration, especially in samples with a low content of sulfates, the color changes already after the first drops of barium chloride. As a result, the titration should be carried out slowly, with vigorous stirring, continuing it until the blue-violet color returns within 2-3 minutes.

The titration is repeated and, if the discrepancy between parallel titrations does not exceed 0.04, the average value of the volume of the barium chloride solution is taken as the result. Otherwise, repeat the titration until an acceptable discrepancy is obtained.

12. Processing of measurement results

12.1. The mass concentration of sulfates in the analyzed water sample is found by the formula:

where X is the mass concentration of sulfates in water, ;

V is the volume of barium chloride solution used for sample titration, ;

Barium chloride solution concentration, equivalent;

Correction equal to 5.0 in the range of mass concentrations of sulfates 50-100; at concentrations above 100

Volume of water sample taken for titration after cationization, .

48.03 - molar mass equivalent, g / mol.

If the mass concentration of sulfates in the analyzed sample exceeds the upper limit of the range (300 ), take an aliquot of the cationic sample, dilute it with distilled water so that the mass concentration of sulfates is within the regulated range, take 10 and perform titration in accordance with paragraph 11.

In this case, the mass concentration of sulfates in the analyzed water sample X is found by the formula:

where is the mass concentration of sulfates in a diluted water sample, ;

v is the volume of an aliquot of a water sample taken for dilution, ;

Volume of water sample after dilution, .

12.2. The result of the analysis is taken as the arithmetic mean of two parallel determinations and :

for which the following condition is satisfied:

where r is the repeatability limit at Р = 0.95.

The value of r at Р = 0.95 for the entire regulated range of mass concentrations of sulfates is 14%.

If a water sample has been diluted due to the mass concentration of sulfates exceeding the upper range limit, the value is selected from Table 1 for the mass concentration of sulfates in the diluted water sample.

It is permissible to present the result of the analysis in the documents issued by the laboratory in the form:

given that ,

where is the result of the analysis obtained in accordance with the prescription of the methodology;

The value of the characteristic of the error of the results of the analysis, established during the implementation of the methodology in the laboratory, and provided by the control of the stability of the results of the analysis.

The numerical values ​​of the measurement result must end with a digit of the same digit as the values ​​of the error characteristic.

Note. When presenting the result of the analysis, the documents issued by the laboratory indicate:

The number of results of parallel determinations used to calculate the result of the analysis;

Method for determining the result of the analysis (arithmetic mean or median of the results of parallel determinations).

14. Quality control of the analysis results when implementing the methodology in the laboratory

Quality control of the analysis results when implementing the methodology in the laboratory provides for:

Operational control of the analysis procedure (based on the assessment of the error in the implementation of a single control procedure);

Control of the stability of the results of the analysis (based on the control of the stability of the standard deviation of repeatability, standard deviation of intralaboratory precision, error).

14.1. Algorithm for operational control of the analysis procedure using the additive method

Operational control of the analysis procedure is carried out by comparing the result of a single control procedure with the control standard K.

The result of the control procedure is calculated by the formula:

where - the result of the analysis of the mass concentration of sulfates in a sample with a known additive - the arithmetic mean of two results of parallel determinations, the discrepancy between which satisfies the condition (1) of section 12.2;

The result of the analysis of the mass concentration of sulfates in the original sample is the arithmetic mean of two results of parallel determinations, the discrepancy between which satisfies the condition (1) of section 12.2;

Addition value.

where , are the values ​​of the error characteristic of the analysis results, established in the laboratory when implementing the methodology, corresponding to the mass concentration of sulfates in the sample with a known additive and in the original sample, respectively.

C - certified value of the sample for control.

The control standard K is calculated by the formula:

where is the error characteristic of the analysis results corresponding to the certified value of the control sample.

Note. It is permissible to establish the error characteristic of the analysis results when implementing the methodology in the laboratory on the basis of the expression: , with subsequent refinement as information accumulates in the process of monitoring the stability of the analysis results.

The analysis procedure is considered satisfactory if the following condition is met:

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MINISTRY OF ENVIRONMENT
AND NATURAL RESOURCES OF THE RUSSIAN FEDERATION

QUANTITATIVE CHEMICAL ANALYSIS OF WATER

MEASUREMENT TECHNIQUE
MASS CONCENTRATION OF NICKEL IONS
IN SAMPLES OF DRINKING, NATURAL AND WASTE WATER
METHOD OF STRIPPING VOLTAMMETRY

PND F 14.1:2:4.73-96

The methodology is approved for the purposes of state environmental control.

Moscow 1995

The methodology was reviewed and approved by the Main Directorate for Analytical Control and Metrological Support of Environmental Activities (GUAC) and the Chief Metrologist of the Ministry of Natural Resources of the Russian Federation

Chief metrologist of the Ministry of Natural Resources of the Russian Federation

Head of GUAC G.M. Tsvetkov.

1. PURPOSE.

This document establishes a method for the quantitative chemical analysis of samples of natural, drinking and waste water to determine nickel ions in them at a nickel mass concentration of 1 to 2500 µg/dm 3 . When determining the content of nickel (II) ions in water samples, the concentration of organic carbon in the electrolyzer of an electrochemical cell should not exceed 10 mg/dm 3 . The interfering effect of the organic component of waters with an organic carbon content above 10 mg/dm 3 is eliminated by processing the sample with ultraviolet irradiation. The interfering effect of a 100-fold excess of copper (II) ions, a 50-fold excess of cadmium ions ( II ) and a 10-fold excess of Co (II) ions are eliminated by adding pyridine.

2. NORMS OF MEASUREMENT ERROR.

The error rates for measuring the mass concentration of nickel ions are regulated by GOST 27384-87 “Water. Norms of measurement error of indicators of composition and properties.

3. VALUES OF THE CHARACTERISTICS OF THE ERROR.

The method of quantitative chemical analysis provides, with a probability of P = 0.95, obtaining the results of the analysis of the mass concentrations of nickel ions with an error not exceeding the values ​​given in the table.

Table 1

Values ​​of measurement error characteristic and its components.

Table #3

The intensity of the smell of water.

Odors of artificial origin (from industrial emissions, for drinking water - from water treatment with reagents at waterworks, etc.) are named according to the corresponding substances: chlorophenol, camphor, gasoline, chlorine, etc.

The odor intensity is also evaluated at 20 and 60 C according to a 5-point system according to the table.

The smell of water should be determined in a room in which the air has no foreign smell. It is desirable that the nature and intensity of the odor be noted by several investigators.

CONCLUSION: The water of the Oktyabrsky district has a weak, barely perceptible unpleasant odor, the water of the Ulba district has no noticeable odor, the water of the KSHT has a weak, indefinite odor.

Determination of water quality by chemical analysis methods.

Experience No. 5 Hydrogen indicator(pH)

Drinking water should have a neutral reaction (pH about 7). The pH value of water in water bodies for household, drinking, cultural and community purposes is regulated within the range of 6.5 - 8.5.

The pH value can be estimated in different ways.

1. The approximate pH value is determined as follows.

Pour 5 ml of the test water, 0.1 ml of a universal indicator into a test tube, mix and determine the pH by the color of the solution:

Pink - orange - pH about 5

Light yellow - 6

Greenish - blue - 8

2. You can determine the pH using universal indicator paper, compare its color with the scale.

3. The most accurate pH value can be determined on a pH meter or Alyamovsky set scale.

According to the results of our research:

Oktyabrsky district - pH about 6 - acidic

Ulba district - pH is about 5 - acidic

KSHT pH - about 5 - acidic

CONCLUSION: Increased acidity in the water of the Ulba, Oktyabrsky districts and KSHT indicates the poor quality of the studied water. Such water adversely affects the human body, and can cause diseases of the gastrointestinal tract.

Experiment No. 6 Determination of chlorides and sulfates

The concentration of chlorides in reservoirs - sources of water supply is allowed up to 350 mg / l.

A lot of chlorides enter water bodies with discharges of household and industrial wastewater. This indicator is very important in assessing the sanitary condition of the reservoir. Table No. 4

Qualitative determination of chlorides with an approximate quantitative assessment is carried out as follows. Take 5 ml of test water into a test tube and add 3 drops of 10% silver nitrate solution. The approximate content of chlorides is determined by sediment or turbidity (see table).

Determination of chloride content

Where, 1.773 is the mass of chloride ions (mg) equivalent to 1 ml of exactly 0.05 N. silver nitrate solution; V-volume of silver nitrate solution used for titration, ml.

To calculate from experience, we took 8mg / l (silver nitrate)

X \u003d (1.773 * 8 * 1000) / 100 \u003d 141.84 mg / l

Conclusion: in water KSHT - strong turbidity, about 10-50 mg / l of chlorides; Ulba and Oktyabrsky districts - weak turbidity, about 1-10 mg/l;

Qualitative determination of sulfates with an approximate quantitative assessment is carried out as follows:

Add 10 ml of test water, 0.5 ml of hydrochloric acid (1:5) and 2 ml of a 5% barium chloride solution to a test tube, mix. The approximate content of sulfates is determined by the nature of the precipitate: in the absence of turbidity, the concentration of sulfate ions is less than 5 mg/l; with weak turbidity, which does not appear immediately, but after a few minutes - 5-10 mg / l; with a weak turbidity that appears immediately after the addition of barium chloride, -10-100 mg / l; strong, rapidly settling turbidity indicates a fairly high content of sulfate ions (more than 100 mg/l).

KShT - pronounced turbidity, 10-100 mg / l; Ulba district - weak turbidity, 5-10 mg/l; Oktyabrsky district - weak turbidity, formed immediately after the addition of barium chloride, 10-100 mg / l;

CONCLUSION: A significant excess of MPC was found in the studied water of the Oktyabrsky district and KSHT, which can cause some cardiovascular diseases.

Experiment No. 7 Detection of phosphate ions.

Reagent: ammonium molybdate (12.5 g (NH 4) 2 MoO 4 dissolve in distilled H 2 O and filter, bring the volume with distilled water to 1 l); nitric acid (1:2); tin chloride.

2.0 ml of ammonium molybdate is added to 5 ml of acidified water sample and tin chloride solution is added dropwise (6 drops). The color of the solution is blue when the concentration of phosphate ions is more than 10 mg/l, blue is more than 1 mg/l, pale blue is more than 0.01 mg/l.

CONCLUSION: In the water of the Ulba region and KSHT, the color of the solution is pale blue, the content of phosphate ions is more than 0.01 mg/l, the color of the solution is blue - more than 1 mg/l.

Experience No. 8 Detection of nitrate - ions.

Reagent: diphenylamine (1g (C 6 H 5) 2 NH dissolved in 100 ml H 2 SO 4)

The reagent is added dropwise to 1 ml of water sample. Pale blue coloration is observed when the concentration of nitrate ions is more than 0.001 mg/l, blue - more than 1 mg/l, blue - more than 100 mg/l.

CONCLUSION: the concentration of nitrate ions from all three water intakes is the same, more than 0.001 mg/l

Qualitative and quantitative detection of heavy metal cations

Methods of analysis: qualitative analysis, including a fractional method developed by N.A. Tanaev. He discovered a number of new, original reactions that make it possible to detect any particular cation in a solution in the presence of a large number of other cations, without resorting to their preliminary precipitation. Quantitative analysis, including the atomic emission method based on the emission of atomic spectra of a substance excited in hot light sources, as well as comparison and generalization of information with literary sources.

Experiment No. 9 Detection of lead ions (Pb 2+ )

Reagent: potassium chromate (10 g K 2 CrO 4 dissolved in 90 ml H 2 O)

5 ml of water sample is placed in a test tube, 1 ml of reagent solution is added. If a yellow precipitate falls out, the content of lead cations is more than 100 mg/l; if cloudiness of the solution is observed, the concentration of lead cations is more than 20 ml/l, and in case of opalescence - 0.1 mg/l

CONCLUSION: The highest content of lead in KSHT water is more than 100 mg/l yellow precipitate; October region - turbidity, more than 20 mg / l; Ulba district - opalescence, 0.1 mg/l.

Experiment No. 10 Detection of calcium ions (Ca 2+ )

Reagents: ammonium oxalate (17.5 g (NH 4) 2 C 2 O 4 dissolve in water and bring to 1 l); acetic acid (120 ml of ice-cold CH 3 COOH to bring with distilled water to 1 l).

3 ml of acetic acid is added to 5 ml of water sample, then 8 ml of the reagent is added. If a white precipitate falls out, then the concentration of calcium ions is 100 mg/l; if the solution is cloudy - the concentration of calcium ions is more than 1 mg / l, with opalescence - more than 0.01 mg / l.

CONCLUSION: The highest content of calcium ions in the sample from the Oktyabrsky district is 100 mg / l, KSHT and Ulba district, cloudiness of the solution is observed - the concentration of ions is more than 1 mg / l

Experiment No. 11 Detection of iron ions (Fe 2+ )

5 ml of the test water sample is placed in a test tube, a few drops of K 3 red blood salt are added. The color of the solution acquires a color called: turbulin blue

CONCLUSION: The highest content of iron 2 ions is found in water with KSHT, because in terms of color brightness, water from KSHT is in the first place, Ulba district is in second place, and Oktyabrsky district is in third place.

Experiment No. 12 Detection of iron ions (Fe3+)

We put 5 ml of a water sample in a test tube, add a few drops of K 4 yellow blood salt. The color of the solution acquires a color called: Prussian blue.

CONCLUSION: The highest content of iron ions3 in water from the Oktyabrsky district is a bright, saturated color, in the remaining two samples the color is less saturated.

Having received the results of the experiment, we turned to an alternative, i.e. the possibility of replacing tap water with melted water.

2.2 Structure of water

The water molecule has an angular structure; the nuclei included in its composition form an isosceles triangle, at the base of which there are two protons, and at the top - the nucleus of the oxygen atom, the O-H internuclear distances are close to 0.1 nm, the distance between the nuclei of hydrogen atoms is 0, 15 nm. Of the eight electrons that make up the outer electron layer of the oxygen atom in the water molecule, two electron pairs form covalent O-N connections, and the remaining four electrons are two unshared electron pairs.

The oxygen atom in the water molecule is in the state of sp2 hybridization. Therefore, the HOH bond angle (104.3°) is close to tetrahedral (109.5°). The electrons that form O-H bonds are shifted to the more electronegative oxygen atom. As a result, hydrogen atoms acquire effective positive charges, since two positive poles are created on them. The centers of negative charges of the unshared electron pairs of the oxygen atom, located in hybrid orbitals, are displaced relative to the atomic nucleus and, in turn, create two negative poles.

The molecular weight of vaporous water is 18 units. But the molecular weight of liquid water, determined by studying its solutions in other solvents, turns out to be higher. This is due to the fact that in liquid water there is an association of individual water molecules into more complex aggregates (clusters). This conclusion is also confirmed by the anomalously high values ​​of the melting and boiling points of water. The association of water molecules is caused by the formation of hydrogen bonds between them. In its structure, water is a hierarchy of regular volumetric structures, which are based on crystal-like formations consisting of 57 molecules and interacting with each other due to free hydrogen bonds. This leads to the appearance of second-order structures in the form of hexagons, consisting of 912 water molecules.

The properties of clusters depend on the ratio in which oxygen and hydrogen come to the surface. The configuration of water elements reacts to any external impact and impurities, which explains the extremely labile nature of their interaction. In ordinary water, the totality of individual water molecules and random associates is 60% (destructured water), and 40% are clusters (structured water).

In solid water (ice), the oxygen atom of each molecule is involved in the formation of two hydrogen bonds with neighboring water molecules. The formation of hydrogen bonds leads to such an arrangement of water molecules, in which they are in contact with each other with their opposite poles. The molecules form layers, each of which is associated with three molecules belonging to the same layer, and with one from the adjacent layer. The structure of ice belongs to the least dense structures; there are voids in it, the dimensions of which somewhat exceed the dimensions of the molecule.

Natural ice is usually much cleaner than water, since when water crystallizes, water molecules are the first to enter the lattice. Ice may contain mechanical impurities - solid particles, droplets of concentrated solutions, gas bubbles. The presence of salt crystals and brine droplets explains the brackishness of sea ice.
When ice melts, its structure is destroyed. But even in liquid water, hydrogen bonds between molecules are preserved: associates are formed - fragments of ice structures - consisting of a greater or lesser number of water molecules. However, in contrast to ice, each associate exists for a very short time: the destruction of some and the formation of other aggregates is constantly taking place. In the voids of such “ice” aggregates, single water molecules can be located; in this case, the packing of water molecules becomes denser. That is why when ice melts, the volume occupied by water decreases, and its density increases.

Therefore, melt water differs from ordinary water in the abundance of multimolecular regular structures (clusters), in which loose ice-like structures remain for some time. After all the ice has melted, the water temperature rises and the hydrogen bonds within the clusters no longer resist the increasing thermal vibrations of the atoms.

There are suggestions that melt water has some special internal dynamics and a special “biological effect” that can persist for a long time (see, for example, V. Belyanin, E. Romanova, Life, the water molecule and the golden ratio, “Science and life”, issue 10, 2004). It is believed that the melt water after the melting of ice has a certain structured cluster structure. Once in the body, melt water has a positive effect on human water metabolism, helping to cleanse the body.

Later, scientists found an explanation for the phenomenon of melt water - in comparison with ordinary water, there are much fewer impurities, including isotopic molecules, where the hydrogen atom is replaced by its heavy isotope - deuterium. Melt water is considered a good folk remedy for increasing the physical activity of the body, especially after hibernation. The villagers noticed that animals drink this water; as soon as the snow begins to melt on the fields, livestock drink from the puddles of melt water. In the fields where they accumulate melt water, the harvest is richer.

Melt water differs from ordinary water in that after freezing and subsequent thawing, many crystallization centers form in it.

It was found that heating fresh melt water above + 37 ° C leads toloss of biological activity, which is most characteristic ofsuch water. Preservation of melt water at a temperature of +20-22°C is also accompanied by a gradual decrease in its biological activity: after 16-18 hours it is reduced by 50 percent.

Fresh melt water accelerates the recovery processes, increases the body's resistance to infections, reduces the sensitivity of the mucous membrane, and normalizes the tone of the bronchial muscles. In children, when treating pneumonia with inhalations of fresh melt water during the recovery period, coughing stops 2-7 days earlier, dry and wet rales disappear, blood parameters, temperature, and respiratory functions normalize, that is, the recovery process is significantly accelerated. At the same time, the number of complications and the frequency of transition of acute forms of diseases to chronic ones are significantly reduced.

In addition, melt water gives a person a lot of strength, vivacity, energy. It has been repeatedly noted that people who drink melt water become not only healthier, but also more efficient, brain activity, labor productivity, and the ability to easily solve difficult problems increase. The high energy of melt water is especially confirmed by the duration of human sleep, which in some people is sometimes reduced in total - attention - up to 4 hours.

The use of fresh melt water is advisable to maintain optimal conditions for life processes in conditions of overheating, high physical exertion .

2.3 Preparation of melt water.

There are 6 ways to prepare melt water (see Appendix P), we used the 6th method and investigated its qualitative composition.

6. For greater effect, you can use double cleansing.

First let the water settle, then freeze. Wait until a thin first layer of ice forms. This ice is removed - it contains some harmful quick-freezing compounds. Then the water is re-frozen - already up to half the volume and the unfrozen fraction of water is removed. Get very clean and healing water

2.4 Qualitative composition of melt water

Experience No. 2 (coloring)

CONCLUSION: transparent

Experience No. 3 (transparency)

CONCLUSION: 6 cm, meets quality standards

Experience No. 4 (smell)

CONCLUSION: no noticeable odor

Experience No. 5 (hydrogen indicator pH)

pH=7, medium is normal, meets quality standards

Experience No. 6 (determination of chlorides and sulfates)

CONCLUSION: Melt water is transparent, it does not contain chlorides, sulfates - less than 5 mg / l

Experience No. 7 (determination of the lead ion)

CONCLUSION: A slight turbidity is observed, the concentration of lead ions is 0.1 mg/l

Experience No. 8 (determination of the calcium ion)

CONCLUSION: Opalescence - more than 0.01 mg / l

Experience No. 9 (determination of iron ions 2+)

CONCLUSION: in melt water, the amount of iron ions is the smallest of all samples.

Experience No. 10 (determination of iron ions 3+)

Experience No. 11 (determination of phosphate ions)

Experience No. 12 (determination of nitrate ions)

Conclusion.

Thus, in this work:

The qualitative and quantitative composition of drinking water from three water intakes in the city of Ust-Kamenogorsk was studied. The highest content of chlorides and lead cations in the water from KSHT, the highest content of calcium cations in the water of the Oktyabrsky district, the highest content of iron cations in the water of the Ulba district, etc.

The causes of its pollution have been established.

Alternative methods of water purification are shown.

An alternative to drinking water is indicated based on its structure.

The qualitative composition of melt water was studied in comparison with drinking water.

The possibilities of using melt water in animal husbandry are shown,

medicine, crop production.

Having completed this work, we have achieved our goal and we hope that the residents of our city will take seriously the problem of the quality of drinking water, and before drinking tap water, they will think about how this will affect their health in the future. Until measures are taken to improve the quality of water, it is necessary to subject the water to thermal treatment or filtration before drinking.

The novelty of our work is as follows: data on the state of drinking water cannot be constant, the picture changes depending on the change in the situation, therefore the data in our work did not coincide with official studies. In addition, while exploring the possibilities of improving the quality of water, we studied in depth and in detail the features of melt water, methods of its preparation, the results of the impact on the development of living organisms and on the health of our citizens.

We hope that alternative methods purification and desalination proposed in the report will not go unnoticed.

Bibliography:

Alekin O.A. Fundamentals of hydrochemistry.-L .: Gidrokhimizdat, 1953.

Aranskaya O.S., Buraya I.V. Project activity of schoolchildren in the process of teaching chemistry.-M.: Ventana-Graf, 2005.

Belyanin V.S., Romanova E.P. New look.-//Science and life.-2003.-№6.

Kiryanova A.V., Lebedeva I.A. From the experience of the school laboratory.- //Chemistry at school.-2009.-№2.

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The requirements for water quality can be very different and are determined by its intended purpose. To assess the quality of reservoir, natural and waste water, their samples are analyzed. Based on the results of the analysis, conclusions are drawn about the suitability of water for a particular type of consumption, the possibility of using certain cleaning methods. Groundwater analyzes make it possible to predict associated mineral deposits. When analyzing waters, chemical, physical and bacteriological indicators are determined to characterize their properties. The main indicators that determine the suitability of water for a particular sector of the national economy are chemical, since physical (suspended particle content, temperature, color, odor, density, compressibility, viscosity, surface tension) and bacteriological (presence of bacteria) indicators depend on chemical composition water.

Chemical indicators of water quality include:

rigidity;

oxidizability;

environment reaction;

salt composition;

composition of dissolved gases.

total salinity characterizes the presence of mineral and organic impurities in water, the amount of these impurities in the form of total mineralization, dry and dense residues. The total mineralization is the sum of all cations and anions found in the water by analysis. Mineralization is expressed in milligram equivalents of salts in 1 liter of water, or as a percentage, that is, the number of grams of dissolved substances contained in 100 g of solution. The dry residue is the total amount of non-volatile substances present in water in suspended, colloidal and dissolved state, expressed in mg / l. The dry residue is determined by evaporating a water sample, then drying at 105°C and weighing. The solid residue is the dry residue determined from a filtered water sample. Therefore, the difference between the two indicators corresponds to the content of suspended solids in the sample. If the dry residue is calcined at a temperature of 500-600 ° C, then its mass will decrease and a residue called ash will be obtained. The decrease in mass occurs due to the combustion of organic substances, the removal of crystallization water, and the decomposition of carbonates. Loss on ignition is roughly attributed to organic impurities.

Hardness of water due to the presence of ions Sa 2+ and mg 2+ . For most industries, water hardness is the main indicator of its quality. Soap does not foam well in hard water. When hard water is heated and evaporated, scale forms on the walls of steam boilers, pipes, heat exchangers, which leads to excessive fuel consumption, metal corrosion and accidents.

Hardness is quantified as the number of milligram equivalents of calcium and magnesium ions in 1 liter of water (mg-eq / l); 1 mg-eq/l of hardness corresponds to the content of 20.04 mg/l of ions in water Sa 2+ or

12.16 mg/l ions mg 2 + . There are general, carbonate and non-carbonate hardness.

Carbonate hardness is associated with the presence in water of mainly bicarbonates and carbonates of calcium and magnesium, which, when water is boiled, turn into insoluble medium or basic salts and precipitate in the form of a dense precipitate:

Ca(HCO 3 )=CaCO 3 ↓+H 2 O+CO 2

2Mg(HCO 3 ) 2 =(MgOH) 2 CO 3 ↓+3CO 2 +H 2 O

Thus, when boiling, carbonate hardness is eliminated. Therefore, it is also called temporary hardness. It should be noted that during the transition HCO 3 - in CO 3 2 - and when calcium and magnesium carbonates precipitate, a certain amount of ions remains in the water Sa 2+ , mg 2+ , CO 3 2 – corresponding to the solubility product CaCO 3 and (MgOH) 2 CO 3 . In the presence of foreign ions, the solubility of these compounds increases.

Non-carbonate (permanent) hardness is not destroyed by boiling. It is caused by the presence in the water of calcium and magnesium salts of strong acids, mainly sulfates and chlorides.

General Water hardness is the sum of carbonate and non-carbonate hardness and is determined by the total content of dissolved calcium and magnesium salts in water. According to the magnitude of the total hardness, the following classification of natural waters is accepted:

very soft (<1,5 мг-экв/л), мягкие (1,5-3,0 мг-экв/л), средней жесткости (3,0-5,4 мг-экв/л), жесткие (5,4-10,7 мг-экв/л), очень жесткие (>10.7 mg-eq/l).

If concentrations (mg/l) in water are known Ca 2+ , mg 2+ and HCO 3 - , then the stiffness is calculated by the following formulas:

General hardness

Carbonate hardness is equal to concentration (mg/l) [ HCO 3 – ]; if the content of calcium and magnesium ions in water is higher than the amount of bicarbonates:

, where 61.02 is the equivalent mass of the ion HCO 3 – .

If the amount of bicarbonates in the water exceeds the content of calcium and magnesium ions, then the carbonate hardness corresponds to the total hardness. The difference between total and carbonate hardness is non-carbonate hardness: F NK = F O - F To. Hence, F NK is the content Ca 2+ and mg 2 + , equivalent to the concentration of all other anions, including uncompensated bicarbonates.

Oxidability characterizes the content of reducing agents in water, which include organic and some inorganic (hydrogen sulfide, sulfites, ferrous iron compounds, etc.) substances. The value of oxidizability is determined by the amount of oxidizing agent consumed and is expressed as the number of milligrams of oxygen necessary for the oxidation of substances contained in 1 liter of water. Distinguish between general and partial oxidation. The total oxidizability is determined by treating water with a strong oxidizing agent - potassium bichromate K 2 Cr 2 O 7 or potassium iodate KIO 3 . Partial oxidizability is determined by reaction with a less strong oxidizing agent - potassium permanganate ToMNO 4 . According to this reaction, only relatively easily oxidized substances are oxidized.

For the complete oxidation of organic substances contained in water, in which transformations occur according to the scheme

[C]→CO 2

[H]→H 2 O

[P]→P 2 O 5

[S]→SO 3

[ N]→ NH 4 + ,

an amount of oxygen (or oxidizing agent per oxygen) is required, called chemical oxygen demand (COD) and expressed in mg/L.

With any method for determining COD, inorganic reducing agents contained in the sample are oxidized along with organic substances. Then the content of inorganic reducing agents in the sample is determined separately special methods and the results of these determinations are subtracted from the found COD value.

Environment reaction characterizes the degree of acidity or alkalinity of water. The concentration of hydrogen ions in natural waters depends mainly on the hydrolysis of salts dissolved in water, the amount of dissolved carbonic acid and hydrogen sulfide, and the content of various organic acids. Usually, for most natural waters, the pH value varies between 5.5-8.5. The constancy of the pH of natural waters is ensured by the presence of buffer mixtures in it. A change in the pH value indicates the pollution of natural water by sewage.

Salt composition. When analyzing natural waters, the content of mainly main ions in them is determined: Cl – , SO 4 2– , HCO 3 – , CO 3 2– , Ca 2+ , mg 2+ , K + , Na + .

Ion definition Cl – . The determination of the chlorine ion is based on the Mohr argentometric method. The principle of analysis is that when a solution is added to water AgNO 3 a white precipitate of silver chloride is formed:

Cl – + Ag + = AgCl↓

The determination of chloride ions is carried out in the range of pH = 6.5 ÷ 10, so that simultaneously with AgCl no precipitate Ag 2 CO 3 . Carrying out the definition Cl – hinders the presence of bromine, iodine, hydrogen sulfide ions in water, from which they are released by pre-treatment of water.

Ion definition SO 4 2– . The method for determining sulfate ions is based on the low solubility of barium sulfate, which quantitatively precipitates in an acidic environment when a solution of barium chloride is added to water: Ba 2+ + SO 4 2– = BaSO 4 ↓

The ion content is calculated from the mass of the formed precipitate. SO 4 2– .

Determination of CO ions 3 2– and HCO 3 – . These ions are determined by titrating a water sample with solutions of sulfuric or hydrochloric acids in series with the indicators phenolphthalein and methyl orange. The neutralization reaction proceeds in two stages.

The first portions of the acid react with the carbonate ion, forming a hydrocarbonate ion:

CO 3 2– + H + = HCO 3 –

The color of phenolphthalein at pH = 8.4 changes from pink to colorless, which coincides with the state of the solution when only bicarbonates remain in it. The amount of acid used for titration is used to calculate the content of the carbonate ion. The consumption of acids for titration with phenolphthalein is equivalent to the content of half of the carbonates, because the latter are only half neutralized before HCO 3 – . Therefore, the total CO 3 2 - equivalent to twice the amount of acid spent on titration. With further titration in the presence of methyl orange, the reaction of neutralization of bicarbonates occurs:

HCO 3 – + H + → CO 2 + H 2 O

Methyl orange changes color at pH = 4.3, i.e. when only free carbon dioxide remains in solution.

When calculating the content of ions HCO 3 - in water, from the amount of acid used for titration with methyl orange, subtract the amount of acid used for titration with phenolphthalein. Total amount of acid used to neutralize ions IS HE – , SO 3 2– and NSO 3 – characterizes the total alkalinity of water. If the pH of the water is below 4.3, then its alkalinity is zero.

Ion definition Ca 2+ , mg 2+ . There are several methods for detecting and determining the content of ions Sa 2+ and mg 2+ . Adding ammonium oxalate to water (NH 4 ) 2 C 2 O 4 in the presence of calcium ions, a white precipitate of calcium oxalate is formed:

Ca 2+ + C 2 O 4 2– = CaC 2 O 4 ↓

After separating the calcium oxalate precipitate in water, ions can be determined mg 2+ with sodium hydrogen phosphate solution Na 2 HPO 4 and ammonia. In the presence of an ion mg 2 + a fine-crystalline precipitate of magnesium salt is formed:

mg 2+ + HPO 4 2– +NH 3 = MgNH 4 PO 4 ↓

The precipitates obtained are calcined and weighed. Based on the results obtained, the value of calcium and magnesium hardness is calculated.

The fastest and most accurate method for determining Sa 2 + and mg 2 + is a complexometric method based on the ability of the disodium salt of ethylenediaminetetraacetic acid (trilon B)

NaOOCCH 2 CH 2 COONa

N––CH 2 ––CH 2 ––N

HOOCCH 2 CH 2 COOH

form strong complex compounds with calcium and magnesium ions.

When a water sample is titrated with Trilon B, calcium ions are sequentially bound into a complex, and then magnesium ions. The content of calcium ions is determined by titrating water in the presence of an indicator - murexide. Murexide forms a slightly dissociated complex compound with calcium ions, painted in crimson color.

Magnesium ions do not complex with murexide. Trilon B extracts Sa 2+ from its soluble complex with murexide, as a result of which the color of the solution changes to lilac:

The amount of Trilon B consumed for titration determines the content Sa 2 + . By titrating a water sample with Trilon B in the presence of a black chromogen indicator, the total content of Sa 2 + and mg 2 + , that is, the total hardness of the water. Water containing Sa 2 + and mg 2 + , in the presence of black chromogen it turns red due to the formation of a complex with mg 2 + . When titrating water at the equivalence point, the color changes to blue due to the following reaction:

Content mg 2+ calculated by the difference between the total content ( Sa 2+ + mg 2+ ) and content Sa 2 + . The trilonometric determination of each ion is carried out at the pH value at which this ion forms a stronger connection with Trilon B than with the indicator. Buffer solutions are added to the titrated solution to maintain the set pH value. In addition, maintaining set value pH provides a certain color of the indicator. The total hardness of water is determined at pH> 9, calcium - at pH = 12.

Ion definition Na + , K + . It is calculated by the difference between the sum of the meq of the found anions and cations, since water is electrically neutral:

rNa + + rK + + rCa 2+ + rMg 2+ = rCO 3 2- + rHCO 3 – + rSO 4 2 + rCl –

rNa + + rK + = rCO 3 2– + rHCO 3 – + rSO 4 2 + rCl – – rCa 2+ – rMg 2+

With sufficiently high accuracy, all cations present in water can be determined by emission spectroscopy of the dry residue.

Dissolved gases in water are determined by chemical methods or gas chromatography.

Determination of carbon dioxide produced by titration of a water sample with alkali in the presence of an indicator - phenolphthalein:

CO 2 + 2NaOH = Na 2 CO 3 + H 2 O

Determination of dissolved oxygen produced by the iodometric method.

For analysis, a solution of manganese chloride and an alkaline solution of potassium iodide are successively added to the water sample. The method is based on the oxidation of freshly obtained divalent manganese hydroxide with oxygen contained in water:

MnCl 2 + 2NaOH = Mn(OH) 2 + 2NaCl

2Mn(OH) 2 + O 2 = 2MnO(OH) 2 ↓

The amount of brown precipitate of tetravalent manganese hydroxide formed in water is equivalent to the amount of dissolved oxygen. With the subsequent addition of hydrochloric or sulfuric acid to the sample, tetravalent manganese is again reduced to divalent, while oxidizing potassium iodide. This results in the release of free iodine equivalent to the content of tetravalent manganese, or, equivalently, dissolved oxygen in the sample:

MnO(OH) 2 + 2KI + 4HCl→MnCl 2 + 2KCl + 3H 2 O+I 2

The released free iodine is quantified by titration with sodium thiosulfate solution:

I 2 + 2Na 2 S 2 O 3
2NaI + Na 2 S 4 O 6

The iodometric method for determining dissolved oxygen is not applicable to waters containing hydrogen sulfide, since hydrogen sulfide interacts with iodine and underestimates the result. To avoid this error, the hydrogen sulfide contained in the sample is preliminarily bound into a compound that does not interfere with the normal course of the reaction. For this purpose, mercury (II) chloride is usually used:

H 2 S + HgCl 2 = HgS↓ + 2HCl

Definition of H 2 S . Before proceeding to the quantitative determination of hydrogen sulfide, its qualitative presence is determined by its characteristic odor. A more objective quality indicator is lead indicator papers (filter paper impregnated with a solution of lead acetate). When lowered into water containing hydrogen sulfide, lead paper darkens, taking on a yellow (low content), brown (medium content) or dark brown (high content) color.

In aqueous solutions, hydrogen sulfide is present in three forms: undissociated H 2 S, in the form of ions HS – and S 2 – . The relative concentrations of these forms in water depend on the pH of this water and, to a lesser extent, on temperature and total salinity.

If the analyzed water does not contain substances that react with iodine, then hydrogen sulfide and its ions can be determined as follows.

At the heart of the quantitative method of determination H 2 S is the oxidation reaction of hydrogen sulfide with iodine:

H 2 S+I 2 = 2HI + S↓

A certain amount of water is added to an accurately measured acidified solution of iodine, taken in excess of the expected content of hydrogen sulfide. The amount of iodine consumed for the oxidation of hydrogen sulfide is determined by back titration of the iodine residue with thiosulfate. The difference between the amount of thiosulfate solution corresponding to the total amount of iodine taken for analysis and the amount of the same solution used to titrate the iodine residue in the sample is equivalent to the content of hydrogen sulfide in the test sample.